The Sogdian Merchants
The Sogdians never built an empire. They built a network: family firms from Samarkand with agents posted from the Chinese capital to Persia, running caravans, lending money, and translating. Sogdian became the common tongue of the Silk Road, and Sogdians carried Buddhism, Manichaeism, and Christianity east into China alongside the goods. A cache of their private letters, abandoned in a watchtower west of Dunhuang around 313 CE, includes a merchant's wife stranded and unpaid, writing that she would rather be married to a dog.
The path or medium of exchange moves, and a place or power rises or declines because it sits on or off the new route.